Re: Corrected di-el strength of gas

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "john cooper" <tesla-at-tesla-coil-dot-com> 

Hi Bert:

Maybe I'm not following this too well but how in the world is a flammable 
gas, i.e., hydrogen, used in a spark gap?  Totally contained?  Under 
pressure?  I suppose it would need oxygen to burn.  When I picture blasting 
a stream of hydrogen into an uncontained spark gap I also see a flame 
thrower, maybe it's just me but I've no exposure or experience with the 
devices you've mentioned so please excuse my naivete'.  They do sound 
strangely compelling though.

John


---------- Original Message ----------------------------------
From: "Tesla list" <tesla-at-pupman-dot-com>
Date:  Tue, 04 May 2004 12:59:31 -0600

 >Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net>
 >
 >Hi John,
 >
 >Thanks for the table. However, there's apparently more to quenching than
 >can be gleaned by comparing relative dielectric strengths. Although
 >dielectric strength will provide an indication of the voltage standoff,
 >this parameter does not indicate how quickly a previously conducting spark
 >gap will recover its dielectric strength (i.e., how well it will quench).
 >
 >For example, although hydrogen has only about half the dielectric strength
 >of nitrogen, it recovers more quickly from a plasma state to a
 >non-conductive state, giving it superior quenching ability. Hydrogen's
 >small molecules have a higher molecular speed so that heat can be removed
 >more quickly from a recovering gap. Hydrogen was used for high performance
 >multiple-gap switches for spark radio, and it's sometimes even used today
 >for special high-power high reprate spark gaps. Hydrogen and deuterium are
 >also the fastest "fill" gases available for high speed thyratron switches,
 >the low pressure evolutionary cousins of spark gaps.
 >
 >Best regards,
 >
 >-- Bert --
 >--